Field of the Invention
The invention relates to a waste conveyor, in which a feed shaft is connected to a conveyor channel and a worm is disposed in the longitudinal direction of the conveyor channel.
The waste conveyor is used for thermal waste disposal, especially according to the low-temperature carbonization combustion process.
In the field of waste disposal, the so-called low-temperature carbonization combustion process has become known. The process and a system operating according to that process for thermal waste disposal are described, for instance, in Published European Patent Application 0 302 310 A1, corresponding to U.S. Pat. No. 4,878,440 as well as in German Published, Non-Prosecuted Patent Application DE 38 30 153 A1. As its essential components, the system for thermal waste disposal according to the low-temperature carbonization combustion process includes a pyrolysis reactor and a high-temperature combustion chamber. The pyrolysis reactor converts waste which is fed through a waste conveyor of the type referred to at the outset, into low-temperature carbonization gas and pyrolysis residue. The low-temperature carbonization gas and the pyrolysis residue are then delivered, after suitable preparation, to a burner of a high-temperature combustion chamber. That produces molten slag, which can be removed through an outlet and which is in vitrified form after it cools down. The flue gas which is produced is sent through a flue gas line to a chimney serving as an outlet. A waste heat steam generator acting as a cooling device, a dust filter system, and a flue gas cleaning system, in particular, are built into the flue gas line. A gas compressor, which is disposed directly at the outlet of the flue gas cleaning system and may be constructed as a suction blower, is also located in the flue gas line. The built-in gas compressor serves to transport gas through the system and in particular to maintain a negative pressure, however slight, in the pyrolysis drum. That negative pressure prevents low-temperature carbonization gas from escaping to the outside environment through ring seals of the pyrolysis drum.
It has been found that in a low-temperature carbonization combustion system the waste conveyor can be blocked or impeded, if excessively large particles of waste fall from the feed shaft into the worm. As a rule, the waste is comminuted beforehand. However, it is possible for the portion of the coil that is rotating just below the feed shaft to already be filled up to a certain level, so that a waste particle, such as a piece of wood falling in, cannot slide any farther inward and jam at the corner of the feed shaft. There is also the danger of the corner of the feed shaft and/or the edge of the worm becoming damaged because of the jamming action.